(19)

(11)

EP 4 055 247 A1

(12)

(43) Date of publication: 14.09.2022 Bulletin 2022/37 (21) Application number: 20885909.0 (22) Date of filing: 06.11.2020

(51) International Patent Classification (IPC):  E21B 29/12(2006.01) B24C 1/00(2006.01) E02D 9/04(2006.01) (52) Cooperative Patent Classification (CPC): B24C 1/003; B24C 1/045; B24C 3/32; B24C 9/00; E21B 29/12; E02B 2017/0052; E02B 17/0034 (86) International application number: PCT/MY2020/050136 (87) International publication number: WO 2021/091368 (14.05.2021 Gazette 2021/19)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA ME Designated Validation States: KH MA MD TN (30) Priority: 06.11.2019 MY PI2019006497 (71) Applicant: Petroliam Nasional Berhad (Petronas) 50088 Kuala Lumpur (MY)	(72) Inventor: THIYAHUDDIN, Mohd Izzat Mohd Kuala Lumpur, 50088 (MY) (74) Representative: Marks & Clerk LLP  15 Fetter Lane London EC4A 1BW London EC4A 1BW (GB)